int insert_resource (struct resource * parent, struct resource * new);
Returns 0 on success, -EBUSY if the resource can't be inserted.
This function is equivalent of request_resource when no conflict happens. If a conflict happens, and the conflicting resources entirely fit within the range of the new resource, then the new resource is inserted and the conflicting resources become childs of the new resource. Otherwise the new resource becomes the child of the conflicting resource